<template>
    <div class="upload-file">
        <el-upload
            :action="uploadFileUrl"
            :before-upload="handleBeforeUpload"
            :file-list="fileList"
            :limit="1"
            :on-error="handleUploadError"
            :on-exceed="handleExceed"
            :on-success="handleUploadSuccess"
            :show-file-list="false"
            :headers="headers"
            class="upload-file-uploader"
            ref="upload"
        >
            <!-- 上传按钮 -->
            <el-button size="mini" type="primary">选取文件</el-button>
            <!-- 上传提示 -->
            <div class="el-upload__tip" slot="tip" v-if="showTip">
                请上传
                <template v-if="fileSize">
                    大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b>
                </template>
                <template v-if="fileType">
                    格式为
                    <b style="color: #f56c6c">{{ fileType.join("/") }}</b>
                </template>
                的文件
            </div>
        </el-upload>

        <!-- 文件列表 -->
        <transition-group
            class="upload-file-list el-upload-list el-upload-list--text"
            name="el-fade-in-linear"
            tag="ul"
        >
            <li
                :key="file.uid"
                class="el-upload-list__item ele-upload-list__item-content"
                v-for="(file, index) in list"
            >
                <el-link :href="file.url" :underline="false" target="_blank">
                    <span class="el-icon-document">
                        {{ getFileName(file.name) }}
                    </span>
                </el-link>
                <div class="ele-upload-list__item-content-action">
                    <el-link
                        :underline="false"
                        @click="handleDelete(index)"
                        type="danger"
                        >删除</el-link
                    >
                </div>
            </li>
        </transition-group>
    </div>
</template>

<script>
import { getToken } from "@/utils/auth";

export default {
    props: {
        // 值
        value: [String, Object, Array],
        // 大小限制(MB)
        fileSize: {
            type: Number,
            default: 5,
        },
        // 文件类型, 例如['png', 'jpg', 'jpeg']
        fileType: {
            type: Array,
            default: () => ["doc", "xls", "ppt", "txt", "pdf"],
        },
        // 是否显示提示
        isShowTip: {
            type: Boolean,
            default: true,
        },
    },
    data() {
        return {
            uploadFileUrl: process.env.VUE_APP_BASE_API + "/common/upload", // 上传的图片服务器地址
            headers: {
                Authorization: "Bearer " + getToken(),
            },
            fileList: [],
        };
    },
    computed: {
        // 是否显示提示
        showTip() {
            return this.isShowTip && (this.fileType || this.fileSize);
        },
        // 列表
        list() {
            let temp = 1;
            if (this.value) {
                // 首先将值转为数组
                const list = Array.isArray(this.value)
                    ? this.value
                    : [this.value];
                // 然后将数组转为对象数组
                return list.map((item) => {
                    if (typeof item === "string") {
                        item = { name: item, url: item };
                    }
                    item.uid = item.uid || new Date().getTime() + temp++;
                    return item;
                });
            } else {
                this.fileList = [];
                return [];
            }
        },
    },
    methods: {
        // 上传前校检格式和大小
        handleBeforeUpload(file) {
            // 校检文件类型
            if (this.fileType) {
                let fileExtension = "";
                if (file.name.lastIndexOf(".") > -1) {
                    fileExtension = file.name.slice(
                        file.name.lastIndexOf(".") + 1
                    );
                }
                const isTypeOk = this.fileType.some((type) => {
                    if (file.type.indexOf(type) > -1) return true;
                    if (fileExtension && fileExtension.indexOf(type) > -1)
                        return true;
                    return false;
                });
                if (!isTypeOk) {
                    this.$message.error(
                        `文件格式不正确, 请上传${this.fileType.join(
                            "/"
                        )}格式文件!`
                    );
                    return false;
                }
            }
            // 校检文件大小
            if (this.fileSize) {
                const isLt = file.size / 1024 / 1024 < this.fileSize;
                if (!isLt) {
                    this.$message.error(
                        `上传文件大小不能超过 ${this.fileSize} MB!`
                    );
                    return false;
                }
            }
            return true;
        },
        // 文件个数超出
        handleExceed() {
            this.$message.error(`只允许上传单个文件`);
        },
        // 上传失败
        handleUploadError(err) {
            this.$message.error("上传失败, 请重试");
        },
        // 上传成功回调
        handleUploadSuccess(res, file) {
            this.$message.success("上传成功");
            this.$emit("input", res.data.url);
        },
        // 删除文件
        handleDelete(index) {
            this.fileList.splice(index, 1);
            this.$emit("input", "");
        },
        // 获取文件名称
        getFileName(name) {
            if (name.lastIndexOf("/") > -1) {
                return name.slice(name.lastIndexOf("/") + 1).toLowerCase();
            } else {
                return "";
            }
        },
    },
    created() {
        this.fileList = this.list;
    },
};
</script>

<style scoped lang="scss">
.upload-file-uploader {
    margin-bottom: 5px;
}
.upload-file-list .el-upload-list__item {
    border: 1px solid #e4e7ed;
    line-height: 2;
    margin-bottom: 10px;
    position: relative;
}
.upload-file-list .ele-upload-list__item-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: inherit;
}
.ele-upload-list__item-content-action .el-link {
    margin-right: 10px;
}
</style>
